Tarte á l'oignon: Oui, please!

Here in New York, baking season is officially in full swing. While pies, cookies and cakes are must-bakes, there is no reason why you can’t take a gander at an Alsatian specialty, tarte á la oignon.

A tart, in its most classic form, consists of a shell made of short dough filled with an egg-based custard. It’s believed to have originated during the middle ages in Europe as a way of ingeniously re-using leftovers. In the days before refrigeration when spices for preserving food were as precious as gold—literally—tarts really saved the day for many a cook. In fact, one of my professors in Italy once mentioned that “tortelli,” “tortelloni,” “tortellini,” and any other stuffed pasta beginning with “tort—“ was a descendant of this medieval leftover ingenuity.

The dough is a fairly simple one although you should never excessively knead it or else you’ll over-develop the gluten, causing the shell to spring back and shrink from the edges of the tart pan. Instead, treat the dough gently and let your hands learn when the dry and wet ingredients have formed a beautiful, soft, supple round form. It won’t be tense, so when you pinch it won’t recoil back into itself. Rather, the dough will give in and surrender to your hands, letting itself be shaped to your will.

This recipe also calls for blind-baking the shell, meaning it must be baked halfway through before adding the filling. Don’t worry, it’s not as terrifying as it sounds. You’ll be glad to add another skill in your pocket.

Tarte á la oignon


For the tart shell:

  • 8 ounces all purpose flour
  • 3/4 teaspoon kosher salt
  • 8 tablespoons unsalted butter, very cold, cut into cubes
  • 1/4 cup ice cold water, plus more if necessary

For the filling:

  • 1 tablespoon unsalted butter, plus more for the tart pan
  • Flour, for dusting the tart pan
  • 4 ounces bacon, cut into lardons
  • 1 large onion (about 8 ounces)
  • 1 tablespoon Pimentón de la Vera
  • Salt and freshly ground pepper, to taste
  • 1 large egg
  • 1 large egg yolk
  • 3/4 cup whole milk
  • 1/4 cup heavy cream
  • 4-5 ounces Gruyere, grated

Special equipment:

  • 1 8-inch tart pan with a removable bottom
  • 1 rimmed 18-by-13-inch baking sheet
  • Parchment paper round, about 12 inches in diameter


On a clean work surface or in a wide bowl, sift together the flour and salt. Add the cubes of cold butter and cut them into the flour-salt mixture with a pastry scraper, until you get a sandy texture, with no large pieces of butter left.

Form a well in the center of the butter-flour-salt mix and add the water with one hand while incorporating the ingredients with the other, until it just comes together. Continue kneading the dough gently without overworking it (if you pinch and pull a small piece it will recoil back into itself) and form it into a ball. Cover in plastic wrap, place in the refrigerator and let rest for 30 minutes.

On a pan set over medium heat, add 1 tablespoon of unsalted butter followed by the bacon lardons and cook until the bacon is soft and the fat has rendered, about 8 minutes. Remove the bacon from the pan with a slotted spoon and transfer to a plate lined with paper towels. Add the onions to the pan and season with salt, freshly ground pepper, and Pimentón. Continue to cook the onions, stirring frequently, until soft and caramelized, about 20 minutes. If necessary, cover the pan with a lid. When done, transfer the onions to a separate bowl and set aside.

Preheat the oven to 400 degrees Fahrenheit. Lightly butter the tart pan and dust with flour before shaking off any excess.

Lightly flour a clean work surface before removing the relaxed dough from the refrigerator. With a rolling pin, roll out the dough to a diameter of about 10 inches. Carefully pick up the dough by loosely wrapping it around the pin and placing it loosely over the prepared tart pan. With your hands, carefully tuck in and fit the dough into the pan before trimming the excess dough over the edge by rolling the pin over the tart pan. Using the tines of a fork, dock the dough at the bottom of the pan. Then, using your thumb and index finger, pinch and crimp the dough along the edge of the pan. Transfer the tart shell to the refrigerator and let it rest for 30 minutes.

In a separate bowl, combine all the liquid ingredients and set aside.

Remove the tart pan from the refrigerator and place it on a rimmed 18-by-13-inch baking sheet. Place a round piece of parchment paper over the pan, leaving some edges overlapping the pan. Fill the covered tart pan evenly with pastry weights. Transfer the pan to the oven and bake for 10 minutes.

Remove the tart pan from the oven and remove the pastry weights along with the parchment paper. Return the tart shell to the oven and bake for another 10 minutes or until lightly browned. Remove from the oven and let it cool slightly.

Spread the bacon and cooked onions evenly along the bottom of the tart shell. Pour in the liquid ingredients (you may have some leftover which is perfectly fine) and then sprinkle the Gruyere cheese over the surface of the tart. Place in the oven and bake for 30 minutes. Remove from the oven and let it cool slightly before serving.

About the Author

Diana Perez

Food, travel & forks in the road: Culinary & Digital Media | Food Stylist | Recipe Tester | Former Social & Digital Media Coordinator, USA Pavilion at Expo Milano 2015